• 한국소음진동공학회논문집
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• 제24권3호
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• pp.247-252
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• 2014

This paper presents a novel impact sensor which can be fabricated with smart paint made of grapheme. This smart nano paint can be easily installed on structures using a spray-on technique and that can make the sensor low cost and practical. The graphene effectively improves the piezoresistivity of the smart paint and that is available to achieve sensitive impact sensor with high gauge factor. The nano smart-paint can detect sufficient impact to cover the damaged energy range of the composite around 1~3J. The voltage outputs from the sprayed paints show fairly linear responses after signal processing. The impact makes deformation of the structure and it brings change of piezoresistivity of the paint and those converts into voltage output consequently by means of a simple signal processing system. The nano smart paint is lightweight and easily applied to the structural surface, and there is no stress concentration. The nano smart paint is expected to be a cost effective and sensitive multi-functional sensor for composites and other damage monitoring applications in the field of structural health monitoring.

• 한국정밀공학회지
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• 제33권1호
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• pp.17-22
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• 2016

In smart factories, the entire manufacturing process from design to the final product is simulated in a virtual manufacturing environment and optimized before starting production. Suppliers and customers make decisions based on the simulation results. Therefore, effective rendering of the information of the virtual products to suppliers and customers is essential for this manufacturing paradigm. In this study, a method of rendering the surface roughness of the virtual products using a tactile display is presented. A tactile display device comprising a $3{\times}3$ array of individually controlled piezoelectric stack actuators is constructed. The surface topology of the virtual products is rendered directly by controlling the piezoelectric stack actuators. A series of experiments is performed to evaluate the performance of the tactile display device. An electrical discharge machined surface is rendered using the proposed method.

• 한국인터넷방송통신학회논문지
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• 제19권5호
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• pp.135-141
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• 2019

대한민국의 스마트팩토리 추진은 매우 중요한 시점에 와 있다. 국제 경쟁력 확보와 제조업 활성화를 위해 대규모 자금과 인력이 투입되어 IT와 OT의 결합을 추진하지만, IT 공급자 중심으로만 접근하는 소프트웨어 투자는 현장 실정에 맞지 않는 시스템 구축으로 끝날 수 있다. 이로 인해 제조업 현장에서는 스마트팩토리 추진의 반감이 커지거나 제조업 혁신의 피로감마저 느끼게 할 수 있는 문제점이 도사리고 있다. 소규모 기업은 기초 수준부터 점검하고 점진적인 통합형 시스템을 구축해야 IT 투자의 실패를 줄이고 현장에서 활용하는 OT 중심의 스마트팩토리를 구현해야 한다. 이를 위해 공정 시각화 솔루션을 제안하여 기초단계와 ICT 미적용 수준에서 한 단계 혁신하기 방안을 제시하였다.

• 융합정보논문지
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• 제11권4호
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• pp.1-18
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• 2021

본 연구의 목적은 확장된 UTAUT를 활용하여 4차 산업혁명 및 스마트 팩토리 관련 기술의 수용의도와 수용행동에 영향을 미칠 수 있는 영향요인을 연구하는 것이다. 이를 통해 어떠한 영향요인들이 관련 기술의 도입과 수용에 영향을 미치는가를 파악함으로써 제조 기업들의 4차 산업혁명에 대한 대응 및 스마트 팩토리 관련 기술 수용을 위한 전략을 도출하는 것이다. 다양한 제조 기업체들에 대하여 설문조사를 시행하였으며, 167부를 연구에 활용하였다. 연구가설의 검정결과 성과기대, 사회적 영향, 촉진조건, 네트워크 효과, 혁신성은 수용의도에 긍정적이고 유의한 영향을 미친다. 그러나 노력기대는 수용의도에 긍정적인 영향을 미치지만 유의하지 않았다. 수용의도는 수용행동에 긍정적이고 유의한 영향을 미친다. 따라서 4차 산업혁명 대응과 스마트 팩토리 관련 기술의 도입 및 수용과정에서 제조 기업들이 제고하여야 하는 요인들을 명확하게 제시하였다.

• 제어로봇시스템학회논문지
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• 제17권2호
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• pp.176-182
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• 2011

Industrial network, often referred to as fieldbus, becomes an indispensable component for intelligent manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers, numerous fieldbus protocols have been developed. But, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. As an alternative to fieldbus, the Ethernet (IEEE 802.3) technology is being adapted to the industrial environment. However, the crucial technical obstacle of Ethernet is its non-deterministic behavior that cannot satisfy the real-time requirements. Recently, the EtherCAT protocol becomes a very promising alternative for real-time industrial application due to the elimination of uncertainties in Ethernet. This paper focuses on the implementation of the IEC 61800 based real-time EtherCAT network for multi-axis smart driver. To demonstrate the feasibility of the implemented EtherCAT slave module, its synchronization performance is evaluated on the experimental EtherCAT testbed with a single axis smart driver.

• 한국정밀공학회지
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• 제33권1호
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• pp.77-83
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• 2016

Intricate deflection requires many conventional actuators (motors, pistons etc.), which can be financially and spatially wasteful. Novel smart soft composite (SSC) actuators have been suggested, but fabrication complexity restricts their widespread use as general-purpose actuators. In this study, a hybrid manufacturing process comprising 3-D printing and casting was developed for automated fabrication of SSC actuators with $200{\mu}m$ precision, using a 3-D printer (3DISON, ROKIT), a simple polymer mixer, and a compressor controller. A method to improve precision is suggested, and the design compensates for deposition and backlash errors (maximum, $170{\mu}m$). A suitable flow rate and tool path are suggested for the polymer casting process. The equipment and process costs proposed here are lower than those of existing 3D printers for a multi-material deposition system and the technique has $200{\mu}m$ precision, which is suitable for fabrication of SSC actuators.

• 정보보호학회논문지
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• 제26권5호
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• pp.1313-1322
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• 2016

최근 인터넷을 통한 공공 기관이나 금융권에 대한 바이러스 및 해킹 공격이 더욱 지능화, 고도화되고 있다. 특히, 지능형 지속 공격인 APT(Advanced Persistent Threat)가 중요한 사이버 위협으로 주목을 받았는데 이러한 APT 공격은 기본적으로 네트워크상에서 악성 코드의 유포를 통해 이루어진다. 본 논문에서는 스마트 제조 산업에서 사용할 수 있도록 네트워크상에서 전송되는 PE(Portable Executable) 파일을 효과적으로 탐지하고 추출하여 악성코드 분석을 효과적으로 할 수 있는 방법을 제안하였다. PE 파일만 고속으로 추출하여 저장하는 기능을 공개 침입 탐지 툴인 Snort의 전처리기단에서 구현한 후 이를 하드웨어 센서 장치에 탑재하여 실험한 결과, 네트워크상에서 전송되는 악성 의심 코드인 PE 파일을 정상적으로 탐지하고 추출할 수 있음을 확인하였다.

• 한국산업융합학회 논문집
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• 제22권3호
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• pp.281-292
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• 2019

This paper proposed a new technology to control a path forging parts in limited narrow space of manufacturing process automation for smart factory. In the motion control, we adapted the obstacle avoidance technology based on ultrasonic sensors. The new motion control performance test for a mobile robot is experimented in narrow space environments. The travelling path control is performed by a fuzzy control logic. which plays a role for selecting an appropriate behavior in accordance with the situation in the vicinity of the mobile robot. Ultrasonic sensors installed at the front face of the mobile robot are used. In order to update the current position and heading angle of the mobile robot, a new approch is adapted. The reliability is illustrated by simulation and experiments.

• Current Optics and Photonics
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• 제3권2호
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• pp.164-171
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• 2019

Photoluminescence (PL) properties of GaN-based light-emitting diodes (LEDs) were analyzed to study the effects of carrier leakage on the luminescence properties at room temperature. The electrical leakage and PL properties were compared for LEDs showing leakages at forward bias and an LED with an intentional leakage path formed by connecting a parallel resistance of various values. The leakages at the forward bias, which could be observed from the current-voltage characteristics, resulted in an increase in the excitation laser power density for the maximum PL efficiency (ratio of PL intensity to excitation power) as well as a reduction in the PL intensity. The effect of carrier leakages on PL properties was similar to the change in PL properties owing to a reduction of the photovoltage by a reverse current since the direction of the carrier movement under photoexcitation is identical to that of the reverse current. Valid relations between PL properties and electrical properties were observed as the PL properties deteriorated with an increase in the carrier leakage. The results imply that the PL properties of LED chips can be an indicator of the electrical properties of LEDs.

• 한국생산제조학회지
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• 제24권1호
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• pp.103-109
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• 2015

This paper introduces a multi-purpose smart fusion sensor. Normally, this type of sensor can contribute to energy savings specifically related to lighting and heating/air conditioning systems by detecting individuals in an office building. If a fire occurs, the sensor can provide information regarding the presence and location of residents in the building to a management center. The system consists of four sensors: a thermopile sensor for detecting heat energy, an ultrasonic sensor for measuring the distance of objects from the sensor, a fire detection sensor, and a passive infrared sensor for detecting temperature change. The system has a wireless communication module to provide the management center with control information for lighting and heating/air conditioning systems. We have also demonstrated the usefulness of the proposed system by applying it to a real environment.